Progression of parafoveal microvasculature changes in diabetic macular ischemia over the course of one year are detectable using OCT-A, a recent study suggests. Specifically, a larger baseline deep vascular plexus (DVP) foveal avascular zone (FAZ) area is predictive of worsening visual outcomes. Also, larger decreases in superficial vascular plexus (SVP) vessel density (VD) were associated with worsening retinal sensitivity.

This one-year prospective, observational study included 56 eyes with varying levels of diabetic retinopathy (DR). All participants underwent best-corrected visual acuity (BCVA) evaluation, swept-source OCT-A imaging and microperimetry at baseline and again at one year.

Over the one-year follow-up period, 16% of eyes experienced a reduction in BCVA of at least one line, and 7% of eyes saw at least a 5% decrease in retinal sensitivity compared with baseline. DR progressed in 13% of eyes.

Mean SVP FAZ area increased from 0.32mm² to 0.39mm², and parafoveal VD of the DVP decreased from 49.8% to 48.8% at one year compared with baseline. In the multivariate regression analysis, larger baseline DVP FAZ area was associated with worsening BCVA over one year (0.16 logMAR per mm²). In addition, larger decreases in SVP VD (-4.18dB per 10% decrease) were associated with worsening retinal sensitivity over one year.

“We demonstrated the predictive value of structural OCT-A parameters in relation to visual outcomes beyond current established systemic risk factors,” the study authors concluded in their paper. “These associations support the use of OCT-A in the early detection and monitoring of diabetic macular ischemia.”

Tsai ASH, Jordan-Yu JM, Gan ATL, et al. Diabetic macular ischemia: influence of optical coherence tomography angiography parameters on changes in functional outcomes over one year. Invest Ophthalmol Vis Sci. 2021;62:9.